The power dissipation of integrated circuit chips, and the modules containing the chips, continues to increase in order to achieve increases in processor performance. This trend poses cooling challenges at the module, system, rack and data center levels.
In many large server applications, processors along with their associated electronics (e.g., memory, disk drives, power supplies, etc.) are packaged in removable drawer configurations stacked within an electronics rack or frame comprising information technology (IT) equipment. In other cases, the electronics may be in fixed locations within the rack or frame. Conventionally, the components have been cooled by air moving in parallel airflow paths, usually front-to-back, impelled by one or more air moving devices (e.g., fans or blowers). In some cases it has been possible to handle increased power dissipation within a single drawer or system by providing greater airflow, for example, through the use of more powerful air moving devices or by increasing the rotational speed (i.e., RPMs) of existing air moving devices. However, this approach is becoming problematic, particularly in the context of a computer center installation (i.e., data center).
The sensible heat load carried by the air exiting the rack(s) is stressing the capability of the room air-conditioning to effectively handle the load. This is especially true for large installations with “server farms” or large banks of computer racks located close together. In such installations, liquid-cooling is an attractive technology to manage the higher heat fluxes. The liquid absorbs the heat dissipated by the components/modules in an efficient manner. Typically, the heat is ultimately transferred from the liquid coolant to a heat sink, whether air or other liquid. In a liquid-cooling approach, monitoring coolant level at one or more locations within the coolant loop may be desirable. However, this monitoring can be problematic if the liquid-cooled system is to undergo pressurized testing.